Welding Wire Weaving Apparatus for Submerged Arc Welding Carriage

ABSTRACT

A welding wire weaving apparatus for a submerged arc welding carriage includes a truck running in a welding direction, a control panel controlling parameters required for welding and weaving operations, a welding wire reel mounting a welding wire thereon, a welding wire supplier supplying the welding wire to an upper part of a member to be welded, a weaver unit weaving the welding wire transversely, a supplier supporting shaft supporting the welding wire supplier at an upper part of the truck, and a weaver unit connection bar connecting the weaver unit to the supplier supporting shaft. The welding wire supplier includes a supply guiding roller, a compressive supplying roller, a welding wire guide bundle, a needle bearing, a welding wire guide bundle and an insulator formed between the needle bearing and the welding wire guide bundle.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a welding wire weaving apparatus for a submerged arc welding (SAW) carriage, and more particularly to a welding wire weaving apparatus for a SAW carriage, reduced in weight and improved in operational convenience by being installed at a space not hindering the operation of the carriage during weaving of the welding wire.

2. Description of the Related Art

Generally, when welding two parent metals, the parent metals are spaced by an interval, that is, a root gap of 4˜12 mm to facilitate formation of back weld beads. Additionally, to prevent generation of a burn-through from metal being welded, a backing material is attached to back surfaces of the parent metals, and a conductive welding wire is supplied between the parent metals. Thus, welding of the parent metals is enabled.

When constructing a vessel, a Flux Cored Arc Welding (FCAW) method and a Submerged Arc Welding (SAW) method are mostly used. More specifically, the FCAW method and the SAW method are solely or jointly applied for the welding during construction of a vessel. Since a welding heat input of the FCAW method is relatively low, the FCAW method is applied to an initial welding in which possibility of a burn-through is high, to thereby prevent the burn-through. Next, the SAW method is additionally performed several times in accordance with thickness of the parent metal and the root gap, thereby completing the welding process.

Welding method of butt joint, in which thickness of a parent metal is 20 mm and a root gap is 10˜12 mm, according to a conventional art are sequentially illustrated in [Table 1] as follows.

In sequence (A) of [Table 1] wherein the root gap is 10 mm, first and second layers are welded using the FCAW method. Then, the welding process is completed by performing the SAW through 5 passes.

In sequence (B) of [Table 1] wherein the number of SAW passes is reduced from 5 times to 3 times, an inferior welding, that is, lack of fusion (LF) is generated at a sidewall of a groove face due to an inner welding portion being relatively narrower than a outer welding portion which is the characteristic of the SAW weld metal. So as not to cause the LF, therefore, reduction of the number of SAW processes is restricted.

In sequence (C) of [Table 1] wherein the root gap is 12 mm, the number of SAW passes is reduced to 2 times by using a composite wire having high deposition rate and enough width in a weld metal. However, the LF still generates at the sidewall of the groove face due to a significant root gap between the parent metals. Accordingly, it is still hard to reduce the number of SAW passes.

To this end, to solve the above problem, a method for preventing the LF generated at a sidewall of a groove face by weaving a welding wire transversely has been suggested, as disclosed in KR Patent Application No. 10-2007-0022017. Additionally, a welding wire weaving apparatus is disclosed in KR Patent Application No. 10-2007-0030176.

In accordance with the linear weaving apparatus suggested in KR Patent Application No. 10-2007-0030176, however, since several parts including a stepping motor, a weaving slide, a motor driver and a controller need to be mounted to a welding carriage, weight and volume of the whole equipment are increased. Furthermore, due to the weight of the motor and the weaving slide, it becomes difficult to achieve lateral balance of the welding carriage, accordingly making it hard for a welding operator to carry the welding carriage. Also, the welding carriage may be turned over during welding. Moreover, a variety of weaving-related functions of the welding carriage cause increase of the manufacturing cost.

SUMMARY OF THE INVENTION

Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a weaving apparatus for a submerged arc welding (SAW) carriage, capable of being facilely operated by being reduced in weight and installed in a space not hindering the operation of a carriage.

In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a welding wire weaving apparatus for a submerged arc welding (SAW) carriage, comprising a truck running in a welding direction, a control panel controlling parameters required for welding and weaving operations, a welding wire reel mounting a welding wire thereon, a welding wire supplier supplying the welding wire to an upper part of a member to be welded, a weaver unit weaving the welding wire transversely, a supplier supporting shaft supporting the welding wire supplier at an upper part of the truck, and a weaver unit connection bar connecting the weaver unit to the supplier supporting shaft, wherein the welding wire supplier comprises a supply guiding roller connected to a shaft of a supplying motor by a shaft cap, the supply guiding roller having a V-shaped cross-sectional groove to guide therethrough supply of the welding wire to a member being welded, a compressive supplying roller that compresses the welding wire toward the supply guiding roller, a welding wire guide bundle integrally formed with a welding wire guide nozzle and connected to a stepwise decelerator through a tightening screw, a needle bearing having a low frictional resistance for weaving of the welding wire, being disposed between the decelerator and a welding wire guide bundle, an insulator formed between the needle bearing and the welding wire guide bundle to protect the supplying motor from the welding wire applied with electricity.

In accordance with another aspect of the present invention, there is provided a welding wire weaving apparatus for a SAW carriage, comprising a truck running in a welding direction, a control panel controlling parameters required for welding and weaving operations, a welding wire reel mounting a welding wire thereon, a welding wire supplier and weaver unit weaving the welding wire transversely and supplying the welding wire to an upper part of a member to be welded, and a supplier supporting shaft supporting the supplier and weaver unit at an upper part of the truck, wherein the welding wire supplier unit comprises a supply guiding roller connected to a shaft of a decelerator in connection with a supplying motor using a shaft cap to supply therethrough the welding wire to a member being welded, a compressive supplying roller compressing the welding wire toward the supply guiding roller, a welding nozzle connected to the decelerator to guide the welding wire passed through the supply guiding roller and the compressive supplying roller to an upper part of the member being welded, and a decelerator base supporting the decelerator thereon, being connected to a supplier and weaver unit supporter connected with the supporting shaft formed on the truck through a weaving shaft pin.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 shows the overall structure of a welding wire shaft weaving apparatus for a SAW carriage, according to a first embodiment of the present invention;

FIG. 2 and FIG. 3 are a front view and a side view, respectively, of a welding wire supplier according to the present invention;

FIG. 4 is a view showing a welding wire weaver unit according to the present invention;

FIG. 5 is a view showing the overall structure of a weaving apparatus for a SAW carriage according to a second embodiment of the present invention; and

FIG. 6 and FIG. 7 are front and rear views, respectively, of a welding wire supplier and weaver unit shown in FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, first and second exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Embodiment 1

FIG. 1 shows the overall structure of a welding wire shaft weaving apparatus for a submerged arc welding (SAW) carriage according to the embodiment of the present invention.

Referring to FIG. 1, the weaving apparatus comprises a truck 1 running in a welding direction, a control panel 2 controlling parameters required for welding and weaving operations, a welding wire reel 3 mounting a welding wire 4 thereon, a welding wire supplier 5 supplying the welding wire 4 to an upper part of a member to be welded, a weaver unit 6 weaving the welding wire 4 transversely, a supplier supporting shaft 7 supporting the welding wire supplier 5 at an upper part of the truck 1, and a weaver unit connection bar 8 connecting the weaver unit 6 to the supplier supporting shaft 7.

FIG. 2 and FIG. 3 are a front view and a side view, respectively, of the welding wire supplier according to the embodiment of the present invention.

Referring to FIG. 2 and FIG. 3, a supply guiding roller 23 having a V-shaped cross-sectional groove, through which the welding wire 4 is supplied up to the member being welded, is connected to a shaft of a supplying motor 32 using a shaft cap 22. Additionally, a compressive supplying roller 29 is provided to the shaft of the supplying motor 32 to compress the welding wire 4 toward the supply guiding roller 23. A welding wire guide bundle 27 integrally formed with a welding wire guide nozzle 21 is connected to a stepwise decelerator 24 through a tightening screw 28.

A needle bearing 25 having a low frictional resistance for weaving of the welding wire 4 is disposed between the decelerator 24 and a welding wire guide bundle 27. Between the needle bearing 25 and the welding wire guide bundle 27, an insulator 26 is formed to protect the supplying motor 32 from the welding wire 4 applied with electricity.

While a conventional welding wire guide bundle has been statically fixed to the decelerator by a tightening screw, the welding wire guide bundle 27 according to the embodiment of the present invention is movable in lateral directions with respect to the decelerator 24 because the needle bearing 25 is inserted between the welding wire guide bundle 27 and the decelerator 24.

In addition, a stopper 33 is mounted to a front side of the decelerator 24 as shown in FIG. 2 so as to prevent the needle bearing 25 and the insulator 26 from being separated from the decelerator 24.

FIG. 4 shows the welding wire weaver unit according to the embodiment of the present invention.

Referring to FIG. 4, a crank block 31 is connected to a shaft 36 of a weaving motor 37 which is rotated unidirectionally. The crank block 31 is connected to an LM guide block 34 through a crank bar 35.

The LM guide block 34 reciprocates in a longitudinal direction along an LM guide rail 30. The LM guide rail 30 performs lateral movements in connection with the welding wire guide nozzle 21 serving as a path of the welding wire 4.

Here, a weaving width of the welding wire 4 can be controlled by varying the crank block 31 according to distances between the weaving motor shaft 36 and the crank bar 35. During unidirectional rotation of the weaving motor 37, longitudinal movements are absorbed using the LM guide rail 30 having a low frictional resistance whereas lateral movements are used for weaving the welding wire 4 efficiently using the needle bearing 25.

According to the above-described embodiment, the welding operation is not obstructed since the welding wire weaver unit is mounted under the welding wire supplier of the SAW carriage. In addition, the weaving motor 32 which rotates in one direction is convenient to control, without necessitating a dedicated motor driver. Furthermore, the above structure is cost effective.

Embodiment 2

FIG. 5 shows the overall structure of a welding wire weaving apparatus for a SAW carriage according to a second embodiment of the present invention.

As shown in FIG. 5, the welding wire weaving apparatus comprises a truck 51 running in a welding direction, a control panel 52 controlling parameters required for welding and weaving operations, a welding wire reel 53 mounting a welding wire 54 thereon, a welding wire supplier and weaver unit 55 weaving the welding wire 54 transversely and supplying the welding wire 4 to an upper part of a member to be welded, and a supplier supporting shaft 56 supporting the supplier and weaver unit 5 at an upper part of the truck 51.

FIG. 6 and FIG. 7 show front and rear sides of the welding wire supplier and weaver unit shown in FIG. 5 in greater detail.

Referring to FIG. 6 and FIG. 7, an end of the supporting shaft 56 that supports the supplier and weaver unit 55 connected to the truck 51 is connected with a supporter 61 of the supplier and weaver unit 55. The supporter 61 is connected to the welding wire supplier through a weaving shaft pin 62 serving as a weaving shaft. To a rear side of the supporter 61 of the supplier and weaver unit 55, a weaver unit connection board 64 is connected to mount a weaver unit including the weaving motor 65.

A decelerator 83 of a supplying motor 82 is connected on a decelerator base 63 connected with the weaving shaft pin 62. To a shaft of the decelerator 83 which is in connection with the supplying motor 82, a supply guiding roller 84 for supplying therethrough the welding wire 54 to the member being welded is connected by a shaft cap 86. In addition, a compressive supplying roller 85 is provided to compress the welding wire 54 toward the supply guiding roller 84. Also, a welding nozzle 87 is connected to the decelerator 83 to guide the welding wire 54 passed through the supply guiding roller 84 and the compressive supplying roller 85 up to a member to be welded.

The weaving motor 65 and the decelerator 66 are mounted to the weaver unit connection board 64. A rotary disc 68, a rotary guide bar 69, and a guiding bar 70 are connected successively from a shaft 67 of the weaving motor 65, and the guiding bar 70 is also connected to the decelerator base 63.

Weaving of the welding wire according to this embodiment is performed as follows. The rotary disc 68 is rotated by a rotational force of the weaving motor 65 under the control of the control panel. Since the rotary guide bar 69, which is connected with the rotary disc 68 at a position eccentric from the rotary disc 68, is connected to the guiding bar 70, when the rotary disc 68 rotates, the welding wire weaver unit connected with the rotary guide bar 69 and the guiding bar 70 weaves the welding wire 54 with respect to the weaving shaft pin 62.

According to the above welding wire weaver unit mounted to the rear side of the welding wire supplier of the SAW carriage, the welding work is not obstructed and control of the weaving motor 65 is convenient since the weaving motor 65 is unidirectional. Additionally, the above weaver unit does not require a dedicated motor driver nor incur high manufacturing cost.

Here, a weaving width of the welding wire 54 can be controlled through adjustment of relative positions between the rotary guiding bar 69 and the guide bar 70. Also, a weaving angle of the welding wire 54 can be controlled by adjusting connection angles between the supporting shaft 56 and the supplier and weaver unit supporter 61 or by adjusting the position of the weaving shaft pin 62 connecting the supplier and weaver unit supporter 61 and the decelerator base 63.

Result

The result of the welding work performed using the above weaving apparatus is shown in [Table 2] as follows.

As shown in [Table 2], when butt-welding is performed on the same condition that the metal thickness is 22 mm and the root gap is 10 mm, it can be appreciated that the LF occurs when the welding wire is not weaved but the LF does not occur when the weaving is performed with the weaving width of 10 mm.

Although the weaving width is set to 10 mm, the width of the welded part is rather reduced from 41.1 mm to 38.5 mm. Thus, reduction of the weaving width according to the root gap is not required. Within a range under 12 mm of the root gap, the weaving width does not have to be adjusted. In conclusion, the first embodiment and the second embodiment of the present invention can accomplish the same effect.

As apparent from the above description, the present invention provides a weaving apparatus for a SAW carriage, installed in a space not hindering the operation of the carriage, having a simple structure and low weight. Accordingly, risk of turnover of the welding carriage can be reduced during movement and transportation of the welding carriage. Also, the manufacturing cost can be saved. In addition, since the operation of the weaving apparatus is simplified, faulty welding, that is, lack of fusion (LF) generated during SAW performed by weaving a welding wire can be reduced, thereby improving welding quality and productivity.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. 

1. A welding wire weaving apparatus for a submerged arc welding carriage, comprising a truck running in a welding direction, a control panel controlling parameters required for welding and weaving operations, a welding wire reel mounting a welding wire thereon, a welding wire supplier supplying the welding wire to an upper part of a member to be welded, a weaver unit weaving the welding wire transversely, a supplier supporting shaft supporting the welding wire supplier at an upper part of the truck, and a weaver unit connection bar connecting the weaver unit to the supplier supporting shaft, wherein the welding wire supplier comprises: a supply guiding roller connected to a shaft of a supplying motor by a shaft cap, the supply guiding roller having a V-shaped cross-sectional groove to guide therethrough supply of the welding wire to a member being welded; a compressive supplying roller that compresses the welding wire toward the supply guiding roller; a welding wire guide bundle integrally formed with a welding wire guide nozzle and connected to a stepwise decelerator through a tightening screw; a needle bearing having a low frictional resistance for weaving of the welding wire, being disposed between the decelerator and a welding wire guide bundle; an insulator formed between the needle bearing and the welding wire guide bundle to protect the supplying motor from the welding wire applied with electricity.
 2. The welding wire weaving apparatus according to claim 1, wherein, in the weaver unit, a crank block is connected to a shaft of a weaving motor performing unidirectional rotation and also connected to an LM guide block through a crank bar.
 3. The welding wire weaving apparatus according to claim 1, wherein the needle bearing is inserted between the welding wire guide bundle and the decelerator so that the welding wire guide bundle can move in lateral directions relative to the decelerator.
 4. The welding wire weaving apparatus according to claim 2, wherein the LM guide block performs longitudinal movements along an LM guide rail whereas the LM guide rail performs lateral movements in connection with the welding wire guide nozzle which serves as a path of the welding wire.
 5. The welding wire weaving apparatus according to claim 1, wherein the weaving width of the welding wire is adjusted by varying the crank block according to distances between the motor shaft and the crank bar.
 6. The welding wire weaving apparatus according to claim 1, wherein, during unidirectional rotation of the weaving motor, longitudinal movements are absorbed using the LM guide rail having a low frictional resistance whereas lateral movements are utilized in weaving the welding wire using the needle bearing.
 7. A welding wire weaving apparatus for a submerged arc welding carriage, comprising: a truck running in a welding direction, a control panel controlling parameters required for welding and weaving operations, a welding wire reel mounting a welding wire thereon, a welding wire supplier and weaver unit weaving the welding wire transversely and supplying the welding wire to an upper part of a member to be welded, and a supplier supporting shaft supporting the supplier and weaver unit at an upper part of the truck, wherein the welding wire supplier unit includes a supply guiding roller connected to a shaft of a decelerator in connection with a supplying motor using a shaft cap to supply therethrough the welding wire to a member being welded, a compressive supplying roller compressing the welding wire toward the supply guiding roller, a welding nozzle connected to the decelerator to guide the welding wire passed through the supply guiding roller and the compressive supplying roller to an upper part of the member being welded and a decelerator base supporting the decelerator thereon, being connected to a supplier and weaver unit supporter connected with the supporting shaft formed on the truck through a weaving shaft pin.
 8. The welding wire weaving apparatus according to claim 7, wherein the supplier and weaver unit is mounted to a rear side of the supplier and weaver unit supporter through a weaver unit connection board, a rotary disc, a rotary guiding bar and a guide bar are connected successively from a shaft of a weaving motor, and the guiding bar is also connected to the decelerator base.
 9. The welding wire weaving apparatus according to claim 8, wherein, when the rotary disc is rotated by a rotational force of the weaving motor, rotation of the rotary disc is transmitted through the rotary guiding bar and the guide bar and accordingly the welding wire weaver unit including the decelerator base weaves the welding wire with respect to the weaving shaft pin.
 10. The welding wire weaving apparatus according to claim 7, wherein the welding wire supplier unit including the welding wire supplying motor is connected to the weaver unit supporter through the weaving shaft pin, such that the welding wire can be moved forward and backward.
 11. The welding wire weaving apparatus according to claim 7, wherein a weaving width of the welding wire is controlled through adjustment of relative positions between the rotary guiding bar and the guide bar.
 12. The welding wire weaving apparatus according to claim 7, wherein a weaving angle of the welding wire can be controlled by adjusting connection angles between the supporting shaft and the supplier and weaver unit supporter or by adjusting the position of the weaving shaft pin connecting the supplier and weaver unit supporter with the decelerator base.
 13. The welding wire weaving apparatus according to claim 2, wherein the weaving width of the welding wire is adjusted by varying the crank block according to distances between the motor shaft and the crank bar.
 14. The welding wire weaving apparatus according to claim 4, wherein, during unidirectional rotation of the weaving motor, longitudinal movements are absorbed using the LM guide rail having a low frictional resistance whereas lateral movements are utilized in weaving the welding wire using the needle bearing.
 15. The welding wire weaving apparatus according to claim 8, wherein a weaving width of the welding wire is controlled through adjustment of relative positions between the rotary guiding bar and the guide bar. 